CVE-2023-1732: Improper random reading in CIRCL
Impact When sampling randomness for a shared secret, the implementation of Kyber and FrodoKEM, did not check whether crypto/rand.Read() returns an error. In rare deployment cases (error thrown by the Read() function), this could lead to a predictable shared secret.
The tkn20 and blindrsa components did not check whether enough randomness was returned from the user provided randomness source. Typically the user provides crypto/rand.Reader, which in the vast majority of cases will always return the right number random bytes. In the cases where it does not, or the user provides a source that does not, the blinding for blindrsa is weak and integrity of the plaintext is not ensured in tkn20.
Patches The fix was introduced in CIRCL v. 1.3.3
Other sources
When sampling randomness for a shared secret, the implementation of Kyber and FrodoKEM, did not check whether crypto/rand.Read() returns an error. In rare deployment cases (error thrown by the Read() function), this could lead to a predictable shared secret.
The tkn20 and blindrsa components did not check whether enough randomness was returned from the user provided randomness source. Typically the user provides crypto/rand.Reader, which in the vast majority of cases will always return the right number random bytes. In the cases where it does not, or the user provides a source that does not, the blinding for blindrsa is weak and integrity of the plaintext is not ensured in tkn20.
Affected Software
Event History
Frequently Asked Questions
What is the vulnerability ID of this issue?
The vulnerability ID is CVE-2023-1732.
What is the severity rating of CVE-2023-1732?
The severity rating of CVE-2023-1732 is 8.2 (High).
Which software is affected by CVE-2023-1732?
The Cloudflare Circl software version up to 1.3.3 is affected by CVE-2023-1732.
What is the impact of CVE-2023-1732?
This vulnerability could lead to a predictable shared secret in rare deployment cases.
Where can I find more information about CVE-2023-1732?
More information about CVE-2023-1732 can be found at the following link: https://github.com/cloudflare/circl/security/advisories/GHSA-2q89-485c-9j2x